Method of producing a color positive for use in a colored motion picture



Feb. 14, 1933. H, K, FAIRALL. ET A1.

METHOD OF' PRODUCING A COLOR POSITIVE FOR USE IN A COLORED MOTION PI-CTURE Filed Aug. 1'7,

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, 'UNITED STATES PATENT ori-fics maar x. Imam. ummm r. cnnsmn., ornos ANGELES, Vcan:immun. menons, nr imams assmmrmr'rs, lro numrcomn un.. -or Los menus, numana, a consonancia or @einem Y m01) Ol' PBODUGUG .L OOLOB POSITIVE FOB. USE 1I A COLORED Application aled August 17, 1927. Serial Io. 218,488.

Our invention relates to color photography and more particularly to the art of produclng color motion picture films.

Colored motion pictures are produced in 5 several diierent ways and we shall therefore confine our attention to the method, in the production of film for which our invention is'particularly applicable. In this method an object having several colors is lphotographed from the same viewpoint upon two negative films. Interposed between the object and one of these negative films is a transparent n-blue filter and between the object an the other negative film a trans- 18 parent orange-red lter. The negative films are then rlliovedxpfsoii the merlam and tideveloped. une -tive is en provided, having an emufsiii applied to each ofthe opposite faces thereof. This emul- 20 sion is impregnated with a dye to render the iilm opaque and this rmits co nding portions of the two developed negative films to be printed simultaneously upon opposite sides of the positive iilm.

- When the positive lilm hasbeen thus exposed, it is developed and has the opaque dye washed out and is then ready for having the opposite faces thereof colored orange-red and blue respectively. The image of the positive 3 film printed from the negative which was exposed through anorange-red filter is'dyed j or treated chemically to give it a blue color.

The image on the opposite side of the positive is in a similar manner dyed or treated chemically to give it an orange-red color. This positive film is now ready for use in a projecting machine. The projecting beam of light in passing through the positive film is 40 colored blue or orange-red those portions thereof which correspond respectively to the blue or orange-red values o f the object originally photographed.

Our process relates to the production of a colored motionV picture film by means of a subtractive process as from an additive process.

The subtractive primary colors are red, yellow,'and blue, or rhaps more correctly, magenta, yellow, an blue-green. Any twocolor process will necessarily give but an ap roximation of perfect color reproduction.

our process as ordinarily practiced, the

images are not colored orange-red and Agreenblue, respectively, but orange-red and blue. Strictly speaking, these colors are 'noty com-V plementary, but the orange-red dye-toning and blue toning solutions used give substantially complementary color values. By the term complementary color values we Vdo not mean complementary colors in the sense that la physicist would use the terms, but do mean that the colors are such that when said complementary color value images are projected on a screen, substantial color reproduction will be produced. It is true that in gllir process as usually practiced, the greens,

uebut these hues may be obtained b a modification of our proce which will described in detail hereinafter. A color complementary to that rendered by our o -red dyeto process may also be produced by the modi cation referred to.

Several processes are at present used for giving color to th'e silver images on the positive iilm. None of the coloring processes in use'at plresent permit the dense masses only of .ea"c positive image to be colored so that the clear spaces on each remainpclear without a long washing step in the roce, which step is exceedingly detriment due to the tendency of alkali in the water to' attack and damage the colored image. It is an object of our invention to provide a process of coloring -a motion icture film whereby satisfactory colors 4ma given vto `respective images and where y the clear spaces of said images remain Substantially uncolored.

greens Aand green-blues are colored blue, Y

It is another object to provide such a procmwhich operates without damage to the lo Fig. 1 shows a, doublev coated positive film having images omofgosite sides thereoicol-V ored orange-red an lue respectively.

` Figs. 2 and 2a are dia ammatic views illustratin an apparatus or carrying out the l5 process o our invention in the production of a colored positive motion picture film.

In our method an object having several colors is photographed from the same viewvpoint u on two negative filmsv producing substantia y complementa color value images, such as orange-red an green-blue. These may be produced by any of thewell known methods, such as by means of a li ht splitting camera provided with suita le color filters interposed between the object and the L ne atives.

he numeral 18 desi ates a negative film in which an orange-reclflilter was interposed between the object and said negative film, and

22 designates a negative ilm in which a green-blue filter was interposed between the object and said negative film. The negative films 18 and 22 are then removed from the camera and developed.

In order to provide a single, bi-colored film for use in the standard projection machines, a positive film 25 is rovided, having emulsions 26 and 27 provi ed upon opposite faces thereof. Emulsions 26 and 27 areimpregnated with a lightfretardent dye which permits the simultaneous printing of ne atives 18 and 22 on opposite sides of the 25 on the emulsion coatings 26 and 27 respectively. Means `are provided to secure exact superim osed registry of the respective images wit each other.

The positive images 31 and 32 rinted upon the layers of emulsion 26 and 27) by the blue negative and orange-red negative respectively'are complementary to said negatives. The image on the positive 31 is now treated so that it will be colored orange-red, and the image on the positive 32 is treated so it will be colored blue. s the purpose of the positive film 25 is to project an image of the ob- 'ect photographed in its true colors, this will f e substantially accomplished bythe passing -of a projecting beam of light through the corresponding positives 31 and 32, with these 59 disposed in the accurately superimposed relation in which they are printed on opposite sides of the positive film 25.

'Ihe processes at present used for the treating of the positive 25 for coloring the images 35 31 and 32 have certain defects which are Lacasse overcome by the process of our-invention which, may be carried on b the apparatus -dialmmatically shown in igs. 2 and 2a.

apparatus includes a freshpositive feed reel.40, a blue ne ative feed reel 41, an orange-red negative eed reel 42, a printing device 43, blue and orange-red winding reels 44 and 45, a series of tanks 48, 49, 50, 'and 51, a blue toning tank 52, a series of treating tanks 53, 54, 55 56, 57, 58, and 59, a drier itive film winding reel 61. Air jet pipes 2 are mounted ad'acent to the lm as it passes betweenthe ta 51 and the blue toning tank 52. This apparatus is operated in the following manner to carry out our method of producing a double-coatedpcsitive color film:

A supply ofresh double-coated film is provided u on the reel 40 and as the lilm is advanced t rough the apparatus, this freshfllniis drawn from the reel 40 and passed through the printing device 43 between the blue and orange-red negatives which are unwound from the reels 41 and'42 respectively.

After the positive 25 has'been printed, the Y negatives 18 and 22 are wound upon the reels 45 and 44 respectively. 4The rinted positive film then passes through a ii-th of lsoft developer in the tank 48 and after that, through a stop bath formed b y a weak solution of acetic acid which is placed in the tank 49. The printing and developing of the positive 25 are carried on in a dark room but the rcmainder ofthe process may be conducted in the light.

Leaving the tank 49, thefilm 25 passes through a fixing solution in tank 50 after which the film passes through a water wash in the tank 51. Leaving the tank 51, the lilm 25 is practically dried by jets of air blowing at high velocity from the pipe 62 disposed close to the film. The film then passes through a blue toning tank` 52 which completely converts the positive silver image 32, which was printed from the orange-red negative 18, into a blue image.` One formula for the` acid iron-tone solution'or acid ferrie-tone solution placed in the tank 52 is as follows:

Ferrie ammonium oxalate 4.5 grams Potassium ferricyanide 2 grams Ammonium chloride 4 grams Hydrochloric acid 2 cc. Water 500 cc.

rig. 2.

Stock relational Basic 'magentL 1 gram Distilledwater l 250 cc. Glacial acetic acid 5 cc.

iS'toccaolutionB Auramine 1 gram Distilled water ".,250 ec. Acetic acid-; -5 cc. I

For use we take 50 ce. of stock solution A and cc. of stock solution B 53, from which tank the film pinto the tank 54 which contains a solution of orangered dye in which the entire film is bathed or approximatel one minute. The preferred co ors. n n f -The image 31 is chemically converted from.

to a blue colored inorganic vsubformula fort 's dye is as follows:

Potassium oxalate 12 grams Uranium nitrate 32 grams Hydrochloric acid v 32 cc.

Potassium ferricyanide 9 grams Water 4000 cc.

The surplus of the orange-red d e of the formulae given is rinsed from the to going into the uranium solution; furthermore, the dye is removed from the clear portions of the film by some chemical action in the uranium solution and does not need' additional washing.

The oran -red dye in the image 31 is mordanted by t e uranium solution so as to convert the silver image 31 into an orange-red image. The ima e31 is therefore not only a dyed image but a uranium toned image.

The length of time required to complete the orange-red dye-toning in the uranium solution is approximately five to seven minutes. The quantity of dye which mordants.

onto the image increases with time, so that image, and

short immersion will give a slightly colored lprolonged immersion will give a strongly co ored image. After leaving the uranium solution, the film 25 passes through `a water w'ash in the tank 57, a hypo solution in the tank 58, another water was in the tank 59, and then passes through the drier 60 and lis wound up on the winding reel 61. Y K

Before entering the hypo solution, the im-` ages are usually opaque, due to the presence of silver ferrocyanide. The hypo dissolves this silver ferrocyanide, thereby removing all traces of opaqueness from the images.

Owing to the complete transformation of the positive silver image 32 to ablue ima in the tank 52, this side of the film is entire y and 200 cc. Th

"said unconverted silver 'nate color values oftheir respective j values.

unaffected by the` orange-red dye and uranium sollilitienglsothahghehlm 25 wlan wound u nt e Y e o images thpgreof perfectly colored to Iliproiluce a jected'image of the original in ,its natural a silver ima stance and is not affected by the subsequent are remarkably clear when the Where a blue-green or vgreen color is desired for some rticular efect, said color r may b'e obtainV by a modification of our process. The blue toning-.treatment is not carried to completion `in toning tank 52, so that the silver limage is only partially converted, leaving some unaltered silver grains.

is may be accomplished in several ways,

such as by using dilute solutions, or by short-v ening the time of treatment. The subsequent uramum solution acts upon the unconverted silver grains of the blue image to turn the color, which modifies t e blue color of the rest of the blue image Jto give said ima e a green-blue, blue-green, or greenish hue. e resultant coloi` depends upon (1) the amount of silver grains left unaltered after the bluetoning treatment, and (2) the amount of time that the said image is treated in the uranium and dyeing solutions. Obviously, the larger the amount of silver grains left unaltered after the blue-toning treatment, and the long-l er the time of treatment in the uranium and dg'eing lue image will be modified.

In the claims we have used chemically toning to mean the conversion of the silver. image into a colored inorganic substance, and

ains to a yellowish solutions, the more the color of the Y have used dye-toning to mean the conver inorganic substance. The terms red and blue are used in a broad sense, i. e., to desigof ,the sEectrum rather than sing e color y color treatment we mean dyeing, chemically toning, dye-tonin impart- .ing or restoring color and speci cally exf clude removin the opaqueness from an image. By artially converting, or partial-a rtions ly chemica y toning, we mean that the proc! ess of conversion or chemically toning is not carried to completion, in that some offthe silver grains of the image are left unaltered.

Although we have outlined'the use of but 011ev pair ofv substantiallyL complementary p colors, the features of our invention may be utilized in the production of any complementary color values. This may be accomplished by varying the time of the several treatments, by` varying the strength of the solutions, or

by using other dyeing and toning solutions.

Thus, red and green images may be produced by substituting a red dye for the orangered dyes, and by using the modification of our blue tomng treatment as outlined.

r We claim as our invention:

1. In the art of producing a colored m0-.

tion picture film, the processwhich consists in producing images upon said film, treat-l ing certain `of said imageswitha solutiqn' including substantially:

4.5 grams Ferrie ammonium 'oxalate Potassium ferricyanide.. 2 grams Ammonium chloride z v 4 gra-ms H drochloric acid 2v cc.`

ater 500 cc.

washing the excess of said solution from the `images treated, treating said film'withE a solution of red dye, washmg the excess red dye from said lilm, bathing said film in a' solution including substantially: l

Potassium oxalate 12 grams Uranium nitrate 32 grams Hydrochloric aicid. 32 cc. Potassium ferricyanide 9 grams Water 4000 cc.

and washing the excess of said last mentioned solution irom said fihn.

2. A process as outlined in claim 1 in which the red dye comprises a mixture of solutions of basic magenta and auramine.

' 3. In the art of producing a colored motion picture lilm, the process which consists in producin images upon said film, treatin certain o said images with a solution mclu ing substantially:l y

Ferrie ammonium oxalate 4.5 grams Potassium ferricyanide 2 grams Ammonium chloride 4 grams Hydrochloric acid 2 y cc. Water- 500 Acc.

washing the excess of said solution from the images treated, treating said film with a solution of dye having red color characteristics, washin the excess dye having red color characteristics fromsaid film, bath'n'g said film ina solution including substantially:

y Potassium oxalate l 12 grams Uranium nitrate l 32 grams .Hydrochloric acid p 32 cc.

Potassium ferricyanide 9grams. Water 4000 cc.

and washing the excess of said last mentioned solutiongfrom said film.

4. A method `"of produc'ng double coated i color film, including the steps of: roducing images on opposite sides of said fi treat'- ,1 ing the images on one side of said film with an acid iron-tone solution to color said images blue and tosimultaneously render said im- .05 treating the images on the other side of ages impervious tored color treatments; and

' menace fihn with an acid uranium-tone color same red.

solution to I 5. A method of producing double coated color hn, including the steps of: roducing images on opposite-sides of said fi treatinthe images on one side of said fihn with a c treatment by a color-producing agent of a v reddish color; and treating said images on the opposite side of said film to give same a reddish color, using a color-producing agent which comprises an acid uranium-tone solution and which will not treat the alreadytreated images.

7 A method of producing a double coated color film, includingthe steps of: producing images on opposite sides of said film; treating the images on one side of said film to give same a color of one color family, and to simultaneoeusly render same impervious to treatment by a color-producing agent of a comple mentary colorl -family; and treating said images on the opposite side of said film to .ive same a color of a complementary color amily, using a uranium bath which will not treat the already-treated images.

8. A method of producing a double coated color film, including the steps of: producing images on opposite sides of said film; chemically converting the images on one side 0f' said film to give same a bluish color, and to simultaneously render same impervious to 'treatment by a color-producing agent of a complementary color family; and treating said images on the opposite side of said film to give same a reddish color, using a colorproducing agent which will not treat the already-treated images, said color producing agent consisting of an acid uranium-tone so- -lution which includes:

Potassium oxalate 12 grams Uranium nitrate.; 32 grams -Hydrochloric acid 32 cc. Potassium ferricyanide 9 grams.

Water 4000 cc.

9; A method tf pmdacing'duble come color film, including the steps of: producing images on opposite sides of said film; treating the images on one side of said film which in a sin le step colors these images a bluish color ang renders them impervious to a complementary color treatment; and treating `the images on the opposite side of said lm to 've same a reddish color, using a color-.proucing agent in the form of an acid uramumtone solution which will not a''ect the already-treated images.

10. A method of producing double coated color lm, including the steps of: roducingimages on opposite sides of said treating the images on one side of said lm which in a single step colors these images a bluish color and renders them impervious to a complementary color treatment; and immersing the film in a 4liquid color-producing agent which will not aiect the already-treated images, to color the images on the opposite side of said ilm a reddish color.

11. A method of producing a double coated color ilm, including the steps of: producing in registry on opposite sides of sald film,

.20 images of different color values; chemically treating the images on one side of said film to convert same to a bluish color and at the same time render these images non-receptive to a reddish color treatment; and treating the images on the opposite side of said film with a color-producing agent which will give these last-mentioned ima s a reddish color, but which `.will not co or the already-treated images. Y g In testimony whereof, we have hereunto set our hands at Los Angeles, California, this 12th day of August, 1927.

HARRY K. FAIRALL. WILLIAM T. CRESPINEL. 

